Iron is a kind of essential trace element which is the most abundant in the human body, and is involved in multiple biological functions, such as substance metabolism, production of red blood cell, cell division and the like. However, iron deficiency is one of the most important nutritional problems in the world, particularly in developing countries, and iron deficiency is an important reason for the occurrence of anemia.
In 1928, Mackay firstly proved that the iron deficiency is the reason for anemia being prevailed in infants; in 1982, Bunge noted that infants are susceptible to iron deficiency. The incidence of iron deficiency anemia in infants in China was higher. According to the “Prevalence investigation of iron deficiency in children in China”, which was published on Chinese Journal of Pediatrics in 2008, overall prevalence of iron deficiency in children aged 7 months to 7 years was 40.3%, and the prevalence of iron deficiency anemia was 7.8%. Among them, the prevalence of iron deficiency and iron deficiency anemia in infants was as high as 44.7% and 20.5%, respectively. The prevalence of anemia in artificially fed babies was almost twice as high as that in breast-fed babies.
Iron deficiency anemia would affect behavior and intellectual development of infants, thereby decreasing the visual and auditory developmental level as well as the learning ability; pica appeared in some infants, such as those who like eating soil block, chalk and other abnormal matters. In addition, when the infants had iron deficiency, the number of brain cells in infants would be reduced or the functions thereof would be lowered, and anemia would lead to insufficient oxygen being carried, as well as hypoxia in cells of brain and other organs, such that iron deficiency might affect mental development of children. Therefore, alleviating the infant iron deficiency has become one of the major nutrition researches in the world.
As well known, babies with exclusive breast-feeding suffer fewer anemia. Breast milk contains various kinds of nutrients required in infants for growth and development. Although breast milk contains a small amount of iron, it is enough for the baby requirements because of the high absorption rate of iron therein. The absorption rate of iron in breast milk (50-75%) is much higher than that in milk powder provided with the enhanced iron (about 4%).
The iron supplementing compound commonly used in the commercially-available infant formula milk powder is non-heme iron, but the absorption rate of non-heme iron is only 2.57%. Although in the case of the iron deficiency in body, the absorption of rate will be slightly increased, but it is still too low. According to the investigation, it is found that the intake of dietary iron in crowd is usually higher than RDA (AI), but the phenomenon of iron deficiency in body, including iron deficiency anemia and hemoglobin being lower than normal level is very common, this is mainly because the formula milk powder and other complementary food comprise phosphates, carbonates, phytic acid, oxalic acid, tannic acid and the like, which can form insoluble salts with iron, and affect the absorption of iron. Even a small amount of the above compounds exist, the inhibition of iron absorption is quite significant. In addition, the milk powder comprises some inhibiting components in a high concentration (such as calcium and phosphate), and lacks iron-absorption enhancing components (such as vitamin C, lactose, lactoferrin and the like), or the proportion of each component is inappropriate.
Although some formula milk powder manufacturers have started to pay attention to problems of infant iron deficiency or anemia, most of them intend to solve the infant iron-absorption insufficiency by increasing the addition amount of iron or excessively increasing the addition amount of vitamin C. On one hand, excessive iron will lead to the imbalanced metabolism of zinc, copper and other trace elements in the body, resulting in loss of appetite, anorexia, growth retardation, low blood pressure, abnormal cholesterol in infants, thereby increasing the risk of inducing heart disease; on the other hand, excess iron deposition may result in the body aging and the occurrence of various epidemic diseases, thereby leading to body injury; furthermore, excess vitamin C will cause the instability in quality of milk powder, and the acidity thereof will be too high after being brewed, resulting in the destruction of other nutrients, etc. Therefore, none of them can improve the current situation of infant iron deficiency.